1. Field of the Invention
The present invention relates to a light-emitting apparatus and a method of producing the same, and more particularly, to a light-emitting apparatus in which an outputted light of a light-emitting device is converted in wavelength by a color conversion layer, and a method of producing the same.
2. Description of the Related Art
Conventionally, a light-emitting apparatus is known which comprises a package having a bottom and a side wall portion surrounding the bottom so as to define a cup with the bottom. A light-emitting device is contained in the cup, and a light-transmitting member containing a phosphor material which converts, in wavelength, the outputted light of an LED chip is filled in the cup.
In producing such an apparatus, the LED chip is mounted on the bottom of the cup, and then the light-transmitting member containing the phosphor material is filled in the cup. The phosphor material is settled onto the LED chip and onto the bottom of the cup (see FIG. 1 of Jpn. Pat. Appln. KOKAI Publication No. 2006-245020) Alternatively, the phosphor material is spray-coated on the LED chip (see FIG. 5 of Jpn. Pat. Appln. KOKAI Publication No. 2003-318448). Incidentally, as shown in FIG. 1 of Jpn. Pat. Appln. KOKAI Publication No. 2006-245020, the distance from the lower edge of the LED chip to the inner surface of the side wall portion is made large, since a metallic thin wire is connected by bonding to the LED chip and to a wiring pattern formed at the peripheral region around the secured portion of the LED chip on the bottom of the cup, electrically connecting the LED chip and the wiring pattern.
In such a light-emitting apparatus, some of the outputted light of the LED chip, for example, a blue LED is converted into a yellow light by the phosphor material (e.g., YAG), and a white light, which is a mixed color of the blue light and the yellow lights is outputted from the light-emitting apparatus. The conversion amount of the outputted light of the LED chip depends on the distance from the lower edge of the LED chip to the inner surface of the side wall portion.
If the distance from the lower edge of the LED chip to the inner surface of the side wall portion is made large as described above, the light extraction efficiency is lowered. Namely, since the outputted light of the light-emitting device is emitted through the color conversion layer, and some of the light is reflected or absorbed at the bottom of the cup, the light extraction efficiency is lowered.
Further, if the distance from the lower edge of the LED chip to the inner surface of the side wall portion is made large, color irregularity in the outputted light becomes large when the LED chip is mounted at a position offset from the predetermined position. In other words, when the LED chip is mounted at a position offset from the predetermined position, the amount of the phosphor material around the LED chip becomes uneven, leading to different conversion amount of the light emitted from the light-emitting device according to location, resulting in large color non-uniformity.
In addition, the longer the distance from the lower edge of the LED chip to the inner surface of the side wall portion, or the larger the amount of the phosphor material on the region from the lower edge of the LED chip to the inner surface of the side wall portion, the more the blue light from the light emitting device is converted into yellow. The resulting light is significantly different in color from the light emitted from the region where the amount of YAG is small (e.g., the upper surface of the LED chip).
On the other hand, when the light-emitting apparatus is mounted on a circuit board at a high density, the parts of the apparatus is deteriorated or failed due to the heat generated when the light-emitting device emits light. Thus, a light-emitting apparatus superior in heat releasing property and suitable for high density mounting is desired.